Effect of IL-2-Bax, a novel interleukin-2-receptor-targeted chimeric protein, on bleomycin lung injury

The role of lymphocytes in the pathogenesis of lung fibrosis is not clear, but the weight of the evidence supports a pro-fibrotic effect for lymphocytes. The high-affinity interleukin-2 receptor (haIL-2R) is expressed on activated, but not quiescent, T lymphocytes. This selective expression of haIL-2R provides the basis for therapeutic strategies that target IL-2R-expressing cells. We hypothesized that elimination of activated lymphocytes by IL-2R-targeted chimeric proteins might ameliorate lung fibrosis. We investigated the effects of IL-2-Bax, a novel apoptosis-inducing IL-2R-targeted chimeric protein, on bleomycin-induced lung injury in mice. Treatment groups included (i) a single intratracheal instillation of bleomycin and twice-daily intraperitoneal injections of IL-2-Bax; (ii) intratracheal bleomycin and intraperitoneal IL-2-PE66(4Glu), an older-generation chimeric protein; (iii) intratracheal bleomycin/intraperitoneal PBS; (iv) intratracheal saline/intraperitoneal PBS. Lung injury was evaluated 14 days after intratracheal instillation by cell count in bronchoalveolar lavage (BAL) fluid, semi-quantitative and quantitative histomorphological measurements and by biochemical analysis of lung hydroxyproline. Bleomycin induced a BAL lymphocytosis that was significantly attenuated by IL-2-Bax and IL-2-PE66(4Glu). However, morphometric parameters and lung hydroxyproline were unaffected by the chimeric proteins. These results show that IL-2-Bax reduces the lymphocytic infiltration of the lungs in response to bleomycin, but this effect is not accompanied by a decrease in lung fibrosis.     

Mutation of Vav1 adaptor region reveals a new oncogenic activation

Vav family members function as remarkable scaffold proteins that exhibit both GDP/GTP exchange activity for Rho/Rac GTPases and numerous protein-protein interactions via three adaptor Src-homology domains. The exchange activity is under the unique regulation by phosphorylation of tyrosine residues hidden by intra-molecular interactions. Deletion of the autoinhibitory N-terminal region results in an oncogenic protein, onco-Vav, leading to a potent activation of Rac GTPases whereas the proto-oncogene barely leads to transformation. Substitution of conserved residues of the SH2-SH3 adaptor region in onco-Vav reverses oncogenicity. While a unique substitution D797N did not affect transformation induced by onco-Vav, we demonstrate that this single substitution leads to transformation in the Vav1 proto-oncogene highlighting the pivotal role of the adaptor region. Moreover, we identified the cell junction protein β-catenin as a new Vav1 interacting partner. We show that the oncogenicity of activated Vav1 proto-oncogene is associated with a non-degradative phosphorylation of β-catenin at residues important for its functions and its redistribution along the cell membrane in fibroblasts. In addition, a similar interaction is evidenced in epithelial lung cancer cells expressing ectopically Vav1. In these cells, Vav1 is also involved in the modulation of β-catenin phosphorylation. Altogether, our data highlight that only a single mutation in the proto-oncogene Vav1 enhances tumorigenicity.     

Quantifying continuous-flow dielectrophoretic trapping of cells and micro-particles on micro-electrode array

An interdigitated electrode array embedded within a micro-channel with forced flow is shown to enable dielectrophoretic (DEP) characterization of particles and/or cells based on measurements of their trapping percentage over a continuous frequency range. A simplified model of the trapping percentage, using spatial averaging of the convective and DEP force, linearly correlated it to the effective DEP force (in its positive mode). Thus, the Clausius–Mossotti factor was fitted to the experimental data, yielding effective electrical characteristics of the particles and/or cells. Also, the generated trapping percentage curve response over a continuous range of frequencies facilitates sorting and detection based on differences other than just the cross-over frequencies.     

Alternatively spliced lysyl oxidase-like 4 isoforms have a pro-metastatic role in cancer

We previously found LOXL4 to be alternatively spliced in an anatomic site-specific manner in tumors involving the serosal cavities. LOXL4 splice variants were predominantly or exclusively expressed in effusion specimens from ovarian and breast carcinoma patients, and were absent in primary carcinomas. In the present study, LOXL4 full-length or splice variants were overexpressed in ES-2 and MDA-MB-231 cells and their invasive and metastatic potential and microRNA expression profile were evaluated. ES-2 cells were further injected into SCID mice ovaries and the extent of tumor progression and metastases formation were compared. We show that both splice variants have a positive effect on the metastatic potential of cells in vitro and on tumor progression in vivo. In contrast, full-length LOXL4 is not pro-metastatic, and may even be considered as a tumor suppressor. In addition, we show that LOXL4 is a possible splicing target of the oncogenic splicing factors SRSF1 and hnRNP A1. In conclusion, our results point to a significant role for LOXL4 alternative splicing in tumor progression.     

Dose-finding study of imatinib in combination with intravenous cytarabine: feasibility in newly diagnosed patients with chronic myeloid leukemia

The HOVON cooperative study group performed a feasibility study of escalated imatinib and intravenous cytarabine in 165 patients with early chronic-phase chronic myeloid leukemia (CML). Patients received 2 cycles of intravenous cytarabine (200 mg/m(2) or 1000 mg/m(2) days 1-7) in conjunction with imatinib (200 mg, 400 mg, 600 mg, or 800 mg), according to predefined, successive dose levels. All dose levels proved feasible. Seven dose-limiting toxicities (DLTs) were observed in 302 cycles of chemotherapy, which were caused by streptococcal bacteremia in 5 cases. Intermediate-dose cytarabine (1000 mg/m(2)) prolonged time to neutrophil recovery and platelet recovery compared with a standard dose (200 mg/m(2)). High-dose imatinib (600 mg or 800 mg) extended the time to platelet recovery compared with a standard dose (400 mg). More infectious complications common toxicity criteria (CTC) grade 3 or 4 were observed after intermediate-dose cytarabine compared with a standard-dose of cytarabine. Early response data after combination therapy included a complete cytogenetic response in 48% and a major molecular response in 30% of patients, which increased to 46% major molecular responses at 1 year, including 13% complete molecular responses. We conclude that combination therapy of escalating dosages of imatinib and cytarabine is feasible. This study was registered at www.kankerbestrijding.nl as no. CKTO-2001-03.     

Breast Conservation After Neoadjuvant Chemotherapy

Background Tumor downstaging by preoperative neoadjuvant chemotherapy in patients with locally advanced breast tumors allows breast conservation in women who were previously candidates for mastectomy. Nevertheless, lumpectomy success in such cases cannot be fully achieved. The aim of this study was to create a quantitative tool for preoperative evaluation of the success of breast conservation in such patients.Methods The study population included 100 consecutive patients with stage II and III breast cancer who were designated for lumpectomy and 19 patients who were designated for mastectomy. All patients received neoadjuvant therapy. Breast-conserving surgery was offered in accordance with clinical and esthetic criteria. Demographic details and clinical, imaging, and pathologic information were collected from medical files. A decision protocol for classifying patients to lumpectomy or mastectomy was built by using the Classification and Regression Trees procedure based on preoperative characteristics.Results Three factors were found to be the main predictors for successful breast conservation: absence of diffuse microcalcifications as seen in the pretreatment mammogram, a postchemotherapy tumor size of < 25 mm, and the existence of a circumscribed lesion on mammography.Conclusions The use of these criteria as a basis for decision on the type of surgery may decrease the performance of unnecessary procedures.